Printing apparatus and printing method

ABSTRACT

For a printing apparatus, a first conveyance speed for a first printing medium is determined according to first print data to be printed on the first printing medium and a second conveyance speed for a second printing medium is determined according to second print data to be printed on the second printing medium that follows the first printing medium along a conveying path. In a case where the second conveyance speed is equal to the first conveyance speed, a conveyance operation of the second printing medium is started before the first printing medium is discharged from the conveying path. In a case where the second conveyance speed is different from the first conveyance speed, the conveyance operation of the second printing medium is started after the first printing medium is discharged from the conveying path.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to conveyance control of printing mediumin a printing apparatus of a full line type.

Description of the Related Art

Japanese Patent Laid-Open No. 2001-39552 discloses a serial typeprinting apparatus with a configuration in which two sheets aresimultaneously supported at different positions in the conveying path toperform continuous printing efficiently. According to Japanese PatentLaid-Open No. 2001-39552, before a paper sensor detects the trailingedge of a preceding sheet, feeding of the succeeding sheetsucceedingsheet starts, and the timing of conveying the succeeding sheetsucceedingsheet is controlled such that after the paper sensor detects thetrailing edge of the preceding sheet, the paper sensor detects theleading edge of the succeeding sheetsucceeding sheet.

Meanwhile, Japanese Patent Laid-Open No. H6-960(1994) discloses aconfiguration of an inkjet printing apparatus of a full line type inwhich when an image has a high printing density, the conveyance speed ofthe sheet is set at a low speed to keep the drive frequency of the printhead low so that the power consumption will not exceed the upper limitof the electric capacity

However, in the case of a relatively large printing apparatus having along conveying path, if the conveyance speed is changed on an individualsheet basis as disclosed in Japanese Patent Laid-Open No. H6-960(1994),two sheets may need to be conveyed simultaneously in different positionsin the conveying path, making the control difficult. For example, in acase where the conveyance speed of the succeeding sheetsucceeding sheetis set higher than the conveyance speed of the preceding sheet, eventhough a certain interval is provided between the trailing edge of thepreceding sheet and the leading edge of the succeeding sheetsucceedingsheet as in Japanese Patent Laid-Open No. 2001-39552, the succeedingsheetsucceeding sheet may catch up with the preceding sheet and cause apaper jam or the like.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above problem. Thus, anobject thereof is to provide a printing apparatus of a full line typeand a printing method that are capable of continuously printing multiplesheets efficiently without causing a paper jam or the like.

According to a first aspect of the present invention, there is provideda printing apparatus comprising: a conveyance unit configured to conveya first printing medium and a second printing medium that follows thefirst printing medium along a conveying path; a line type print headdisposed in the conveying path and configured to print on a printingmedium according to print data; a determination unit configured todetermine a first conveyance speed for the first printing mediumaccording to first print data to be printed on the first printingmedium, and determine a second conveyance speed for the second printingmedium according to second print data to be printed on the secondprinting medium; and a control unit configured to control the conveyanceunit, wherein in a case where the second conveyance speed is equal tothe first conveyance speed, the control unit starts conveyance operationof the second printing medium before the first printing medium isdischarged from the conveying path, and in a case where the secondconveyance speed is different from the first conveyance speed, thecontrol unit starts the conveyance operation of the second printingmedium after the first printing medium is discharged from the conveyingpath.

According to a second aspect of the present invention, there is provideda printing apparatus comprising: a conveyance unit configured to conveya first printing medium and a second printing medium that follows thefirst printing medium along a conveying path; a line type print headdisposed in the conveying path and configured to print on a printingmedium according to print data; a determination unit configured todetermine a first conveyance speed for the first printing mediumaccording to first print data to be printed on the first printingmedium, and determine a second conveyance speed for the second printingmedium according to second print data to be printed on the secondprinting medium; and a control unit configured to control the conveyanceunit, wherein in a case where the second conveyance speed is equal tothe first conveyance speed, the control unit starts conveyance of thesecond printing medium with a specified distance from the first printingmedium while the first printing medium is being conveyed in theconveying path, in a case where the second conveyance speed is lowerthan the first conveyance speed, the control unit starts the conveyanceof the second printing medium with a distance shorter than the specifieddistance from the first printing medium while the first printing mediumis being conveyed in the conveying path, and in a case where the secondconveyance speed is higher than the first conveyance speed, the controlunit starts the conveyance of the second printing medium with a distancelonger than the specified distance from the first printing medium whilethe first printing medium is being conveyed in the conveying path.

According to a third aspect of the present invention, there is provideda printing method comprising: a conveyance step of conveying a firstprinting medium and a second printing medium that follows the firstprinting medium along a conveying path; a printing step of printing on aprinting medium according to print data, using a line type print headdisposed in the conveying path; a determination step of determining afirst conveyance speed for the first printing medium according to firstprint data to be printed on the first printing medium, and determining asecond conveyance speed for the second printing medium according tosecond print data to be printed on the second printing medium; and acontrol step of controlling the conveyance step, wherein in the controlstep, in a case where the second conveyance speed is equal to the firstconveyance speed, conveyance operation of the second printing medium isstarted before the first printing medium is discharged from theconveying path, and in a case where the second conveyance speed isdifferent from the first conveyance speed, the conveyance operation ofthe second printing medium is started after the first printing medium isdischarged from the conveying path.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a printing apparatus on standby;

FIG. 2 is a control configuration diagram of the printing apparatus;

FIG. 3 is a diagram illustrating the printing apparatus in printing;

FIGS. 4A to 4C are diagrams illustrating the conveying path of theprinting medium fed from a first cassette;

FIGS. 5A to 5C are diagrams illustrating the conveying path of theprinting medium fed from a second cassette;

FIGS. 6A to 6D are diagrams illustrating the conveying path in the caseof performing print operation on the back side of the printing medium;

FIG. 7 is a diagram illustrating the printing apparatus in a maintenancemode;

FIG. 8 is a diagram illustrating the relationship between drive rollersand motors;

FIG. 9 is a flowchart illustrating a conveyance mode setting process ina first embodiment;

FIGS. 10A to 10C are diagrams illustrating the relationship between thetype of dot count value and conveyance speed V;

FIGS. 11A and 11B are diagrams illustrating a state of “continuousconveyance”;

FIGS. 12A to 12C are diagrams illustrating conveyance examples in thefirst embodiment;

FIG. 13 is a flowchart illustrating a conveyance mode setting process ina second embodiment;

FIG. 14 is a diagram illustrating a conveyance example in the secondembodiment;

FIG. 15 is a flowchart illustrating a conveyance mode setting process ina third embodiment;

FIG. 16 is a diagram illustrating an inter-page distance PL settingtable; and

FIG. 17 is a diagram illustrating a conveyance example in the thirdembodiment.

DESCRIPTION OF THE EMBODIMENTS First Embodiment

FIG. 1 is an internal configuration diagram of an inkjet printingapparatus 1 (hereinafter “printing apparatus 1”) used in the presentembodiment. In the drawings, an x-direction is a horizontal direction, ay-direction (a direction perpendicular to paper) is a direction in whichejection openings are arrayed in a print head 8 described later, and az-direction is a vertical direction.

The printing apparatus 1 is a multifunction printer comprising a printunit 2 and a scanner unit 3. The printing apparatus 1 can use the printunit 2 and the scanner unit 3 separately or in synchronization toperform various processes related to print operation and scan operation.The scanner unit 3 comprises an automatic document feeder (ADF) and aflatbed scanner (FBS) and is capable of scanning a documentautomatically fed by the ADF as well as scanning a document placed by auser on a document plate of the FBS. The present embodiment is directedto the multifunction printer comprising both the print unit 2 and thescanner unit 3, but the scanner unit 3 may be omitted. FIG. 1 shows theprinting apparatus 1 in a standby state in which neither print operationnor scan operation is performed.

In the print unit 2, a first cassette 5A and a second cassette 5B forhousing printing medium (cut sheets) S are detachably provided at thebottom of a casing 4 in the vertical direction. Relatively smallprinting medium of up to A4 size are stacked and housed in the firstcassette 5A and relatively large printing medium of up to A3 size arestacked and hosed in the second cassette 5B. A first feeding unit 6A forfeeding housed printing medium one by one is provided near the firstcassette 5A. Similarly, a second feeding unit 6B is provided near thesecond cassette 5B. In print operation, a print medium S is selectivelyfed from either one of the cassettes.

Conveying rollers 7, a discharging roller 12, pinch rollers 7 a, spurs 7b, a guide 18, an inner guide 19, and a flapper 11 are conveyingmechanisms for guiding a print medium S in a predetermined direction.The conveying rollers 7 are drive rollers located upstream anddownstream of the print head 8 and driven by a conveying motor (notshown). The pinch rollers 7 a are follower rollers that are turned whilenipping a print medium S together with the conveying rollers 7. Thedischarging roller 12 is a drive roller located downstream of theconveying rollers 7 and driven by the conveying motor (not shown). Thespurs 7 b nip and convey a print medium S together with the conveyingrollers 7 and discharging roller 12 located downstream of the print head8.

In the printing apparatus, a plurality of motors are provided fordriving the drive rollers. Each of roller is connected one of theplurality of motors. Relationships between multiple motors and driverollers will be explained later.

The guide 18 is disposed in a conveying path of a print medium S toguide the print medium S in a predetermined direction. The inner guide19 is a member extending in the y-direction. The inner guide 19 has acurved side surface and guides a print medium S along the side surface.The flapper 11 is a member for changing a direction in which a printmedium S is conveyed in duplex print operation. A discharging tray 13 isa tray for stacking and housing printing medium S that were subjected toprint operation and discharged by the discharging roller 12.

The print head 8 of the present embodiment is a full line type colorinkjet print head. In the print head 8, a plurality of ejection openingsconfigured to eject ink based on print data are arrayed in they-direction in FIG. 1 so as to correspond to the width of a print mediumS. That is, the print head is configured to eject inks of a plurality ofcolors. When the print head 8 is in a standby position, an ejectionopening surface 8 a of the print head 8 is oriented vertically downwardand capped with a cap unit 10 as shown in FIG. 1. In print operation,the orientation of the print head 8 is changed by a print controller 202described later such that the ejection opening surface 8 a faces aplaten 9. The platen 9 includes a flat plate extending in they-direction and supports a print medium S being subjected to printoperation by the print head 8 from the back side. The movement of theprint head 8 from the standby position to a printing position will bedescribed later in detail.

An ink tank unit 14 separately stores ink of four colors to be suppliedto the print head 8. An ink supply unit 15 is provided in the midstreamof a flow path connecting the ink tank unit 14 to the print head 8 toadjust the pressure and flow rate of ink in the print head 8 within asuitable range. The present embodiment adopts a circulation type inksupply system, where the ink supply unit 15 adjusts the pressure of inksupplied to the print head 8 and the flow rate of ink collected from theprint head 8 within a suitable range.

A maintenance unit 16 comprises the cap unit 10 and a wiping unit 17 andactivates them at predetermined timings to perform maintenance operationfor the print head 8. The maintenance operation will be described laterin detail.

FIG. 2 is a block diagram showing a control configuration in theprinting apparatus 1. The control configuration mainly includes a printengine unit 200 that exercises control over the print unit 2, a scannerengine unit 300 that exercises control over the scanner unit 3, and acontroller unit 100 that exercises control over the entire printingapparatus 1. A print controller 202 controls various mechanisms of theprint engine unit 200 under instructions from a main controller 101 ofthe controller unit 100. Various mechanisms of the scanner engine unit300 are controlled by the main controller 101 of the controller unit100. The control configuration will be described below in detail.

In the controller unit 100, the main controller 101 including a CPUcontrols the entire printing apparatus 1 using a RAM 106 as a work areain accordance with various parameters and programs stored in a ROM 107.For example, when a print job is input from a host apparatus 400 via ahost I/F 102 or a wireless I/F 103, an image processing unit 108executes predetermined image processing for received image data underinstructions from the main controller 101. The main controller 101transmits the image data subjected to the image processing to the printengine unit 200 via a print engine IT 105.

The printing apparatus 1 may acquire image data from the host apparatus400 via a wireless or wired communication or acquire image data from anexternal storage unit (such as a USB memory) connected to the printingapparatus 1. A communication system used for the wireless or wiredcommunication is not limited. For example, as a communication system forthe wireless communication, Wi-Fi (Wireless Fidelity; registeredtrademark) and Bluetooth (registered trademark) can be used. As acommunication system for the wired communication, a USB (UniversalSerial Bus) and the like can be used. For example, when a scan commandis input from the host apparatus 400, the main controller 101 transmitsthe command to the scanner unit 3 via a scanner engine I/F 109.

An operating panel 104 is a mechanism to allow a user to do input andoutput for the printing apparatus 1. A user can give an instruction toperform operation such as copying and scanning, set a print mode, andrecognize information about the printing apparatus 1 via the operatingpanel 104.

In the print engine unit 200, the print controller 202 including a CPUcontrols various mechanisms of the print unit 2 using a RAM 204 as awork area in accordance with various parameters and programs stored in aROM 203. When various commands and image data are received via acontroller FF 201, the print controller 202 temporarily stores them inthe RAM 204. The print controller 202 allows an image processingcontroller 205 to convert the stored image data into print data suchthat the print head 8 can use it for print operation. After thegeneration of the print data, the print controller 202 allows the printhead 8 to perform print operation based on the print data via a head I/F206. At this time, the print controller 202 conveys a print medium S bydriving the feeding units 6A and 6B, conveying rollers 7, dischargingroller 12, and flapper 11 shown in FIG. 1 via a conveyance control unit207.

The conveyance control unit 207 is connected with a detection unit 212and a driving unit 211 and controls a conveyance of the print medium Susing the driving unit 211 based on a result of a detection of thedetection unit 212. The detection unit 212 includes detection members 20detecting presence of the print medium S and encoders detecting amountsof rotation of the driving rollers.

The print head 8 performs print operation in synchronization with theconveyance operation of the print medium S under instructions from theprint controller 202, thereby performing printing.

A head carriage control unit 208 changes the orientation and position ofthe print head 8 in accordance with an operating state of the printingapparatus 1 such as a maintenance state or a printing state. An inksupply control unit 209 controls the ink supply unit 15 such that thepressure of ink supplied to the print head 8 is within a suitable range.A maintenance control unit 210 controls the operation of the cap unit 10and wiping unit 17 in the maintenance unit 16 when performingmaintenance operation for the print head 8.

In the scanner engine unit 300, the main controller 101 controlshardware resources of the scanner controller 302 using the RAM 106 as awork area in accordance with various parameters and programs stored inthe ROM 107, thereby controlling various mechanisms of the scanner unit3. For example, the main controller 101 controls hardware resources inthe scanner controller 302 via a controller FF 301 to cause a conveyancecontrol unit 304 to convey a document placed by a user on the ADF andcause a sensor 305 to scan the document. The scanner controller 302stores scanned image data in a RAM 303. The print controller 202 canconvert the image data acquired as described above into print data toenable the print head 8 to perform print operation based on the imagedata scanned by the scanner controller 302.

FIG. 3 shows the printing apparatus 1 in a printing state. As comparedwith the standby state shown in FIG. 1, the cap unit 10 is separatedfrom the ejection opening surface 8 a of the print head 8 and theejection opening surface 8 a faces the platen 9. In the presentembodiment, the plane of the platen 9 is inclined about 45 degrees withrespect to the horizontal plane. The ejection opening surface 8 a of theprint head 8 in a printing position is also inclined about 45 degreeswith respect to the horizontal plane so as to keep a constant distancefrom the platen 9.

In the case of moving the print head 8 from the standby position shownin FIG. 1 to the printing position shown in FIG. 3, the print controller202 uses the maintenance control unit 210 to move the cap unit 10 downto an evacuation position shown in FIG. 3, thereby separating the capmember 10a from the ejection opening surface 8 a of the print head 8.The print controller 202 then uses the head carriage control unit 208 toturn the print head 8 45 degrees while adjusting the vertical height ofthe print head 8 such that the ejection opening surface 8 a faces theplaten 9. After the completion of print operation, the print controller202 reverses the above procedure to move the print head 8 from theprinting position to the standby position.

Next, a conveying path of a print medium S in the print unit 2 will bedescribed. When a print command is input, the print controller 202 firstuses the maintenance control unit 210 and the head carriage control unit208 to move the print head 8 to the printing position shown in FIG. 3.The print controller 202 then uses the conveyance control unit 207 todrive either the first feeding unit 6A or the second feeding unit 6B inaccordance with the print command and feed a print medium S.

FIGS. 4A to 4C are diagrams showing a conveying path in the case offeeding an A4 size print medium S from the first cassette 5A. A printmedium S at the top of a stack of printing medium in the first cassette5A is separated from the rest of the stack by the first feeding unit 6Aand conveyed toward a print area P between the platen 9 and the printhead 8 while being nipped between the conveying rollers 7 and the pinchrollers 7 a. FIG. 4A shows a conveying state where the front end of theprint medium S is about to reach the print area P. The direction ofmovement of the print medium S is changed from the horizontal direction(x-direction) to a direction inclined about 45 degrees with respect tothe horizontal direction while being fed by the first feeding unit 6A toreach the print area P.

In the print area P, a plurality of ejection openings provided in theprint head 8 eject ink toward the print medium S. In an area where inkis applied to the print medium S, the back side of the print medium S issupported by the platen 9 so as to keep a constant distance between theejection opening surface 8 a and the print medium S. After ink isapplied to the print medium S, the conveying rollers 7 and the spurs 7 bguide the print medium S such that the print medium S passes on the leftof the flapper 11 with its tip inclined to the right and is conveyedalong the guide 18 in the vertically upward direction of the printingapparatus 1. FIG. 4B shows a state where the front end of the printmedium S has passed through the print area P and the print medium S isbeing conveyed vertically upward. The conveying rollers 7 and the spurs7 b change the direction of movement of the print medium S from thedirection inclined about 45 degrees with respect to the horizontaldirection in the print area P to the vertically upward direction.

After being conveyed vertically upward, the print medium S is dischargedinto the discharging tray 13 by the discharging roller 12 and the spurs7 b. FIG. 4C shows a state where the front end of the print medium S haspassed through the discharging roller 12 and the print medium S is beingdischarged into the discharging tray 13. The discharged print medium Sis held in the discharging tray 13 with the side on which an image wasprinted by the print head 8 down.

FIGS. 5A to 5C are diagrams showing a conveying path in the case offeeding an A3 size print medium S from the second cassette 5B. A printmedium S at the top of a stack of printing medium in the second cassette5B is separated from the rest of the stack by the second feeding unit 6Band conveyed toward the print area P between the platen 9 and the printhead 8 while being nipped between the conveying rollers 7 and the pinchrollers 7 a.

FIG. 5A shows a conveying state where the front end of the print mediumS is about to reach the print area P. In a part of the conveying path,through which the print medium S is fed by the second feeding unit 6Btoward the print area P, the plurality of conveying rollers 7, theplurality of pinch rollers 7 a, and the inner guide 19 are provided suchthat the print medium S is conveyed to the platen 9 while being bentinto an S-shape.

The rest of the conveying path is the same as that in the case of the A4size print medium S shown in FIGS. 4B and 4C. FIG. 5B shows a statewhere the front end of the print medium S has passed through the printarea P and the print medium S is being conveyed vertically upward. FIG.5C shows a state where the front end of the print medium S has passedthrough the discharging roller 12 and the print medium S is beingdischarged into the discharging tray 13.

FIGS. 6A to 6D show a conveying path in the case of performing printoperation (duplex printing) for the back side (second side) of an A4size print medium S. In the case of duplex printing, print operation isfirst performed for the first side (front side) and then performed forthe second side (back side). A conveying procedure during printoperation for the first side is the same as that shown in FIGS. 4A to 4Cand therefore description will be omitted. A conveying proceduresubsequent to FIG. 4C will be described below.

After the print head 8 finishes print operation for the first side andthe back end of the print medium S passes by the flapper 11, the printcontroller 202 turns the conveying rollers 7 backward to convey theprint medium S into the printing apparatus 1. At this time, since theflapper 11 is controlled by an actuator (not shown) such that the tip ofthe flapper 11 is inclined to the left, the front end of the printmedium S (corresponding to the back end during the print operation forthe first side) passes on the right of the flapper 11 and is conveyedvertically downward. FIG. 6A shows a state where the front end of theprint medium S (corresponding to the back end during the print operationfor the first side) is passing on the right of the flapper 11.

Then, the print medium S is conveyed along the curved outer surface ofthe inner guide 19 and then conveyed again to the print area P betweenthe print head 8 and the platen 9. At this time, the second side of theprint medium S faces the ejection opening surface 8 a of the print head8. FIG. 6B shows a conveying state where the front end of the printmedium S is about to reach the print area P for print operation for thesecond side.

The rest of the conveying path is the same as that in the case of theprint operation for the first side shown in FIGS. 4B and 4C. FIG. 6Cshows a state where the front end of the print medium S has passedthrough the print area P and the print medium S is being conveyedvertically upward. At this time, the flapper 11 is controlled by theactuator (not shown) such that the tip of the flapper 11 is inclined tothe right. FIG. 6D shows a state where the front end of the print mediumS has passed through the discharging roller 12 and the print medium S isbeing discharged into the discharging tray 13.

Next, maintenance operation for the print head 8 will be described. Asdescribed with reference to FIG. 1, the maintenance unit 16 of thepresent embodiment comprises the cap unit 10 and the wiping unit 17 andactivates them at predetermined timings to perform maintenanceoperation.

FIG. 7 is a diagram showing the printing apparatus 1 in a maintenancestate. In the case of moving the print head 8 from the standby positionshown in FIG. 1 to a maintenance position shown in FIG. 7, the printcontroller 202 moves the print head 8 vertically upward and moves thecap unit 10 vertically downward. The print controller 202 then moves thewiping unit 17 from the evacuation position to the right in FIG. 7.After that, the print controller 202 moves the print head 8 verticallydownward to the maintenance position where maintenance operation can beperformed.

On the other hand, in the case of moving the print head 8 from theprinting position shown in FIG. 3 to the maintenance position shown inFIG. 7, the print controller 202 moves the print head 8 verticallyupward while turning it 45 degrees. The print controller 202 then movesthe wiping unit 17 from the evacuation position to the right. Followingthat, the print controller 202 moves the print head 8 verticallydownward to the maintenance position where maintenance operation can beperformed.

FIG. 8 is a diagram illustrating the relationships between multiplemotors and drive rollers in the printing apparatus 1. A first feedingmotor 22 drives the first feeding unit 6A for feeding printing medium Sfrom the first cassette 5A. A second feeding motor 23 drives the secondfeeding unit 6B for feeding printing medium S from the second cassette5B. A first conveying motor 24 drives a first intermediumte roller 71Awhich first conveys a printing medium S fed by the first feeding unit6A. A second conveying motor 25 drives a second intermediumte roller 71Bwhich first conveys a printing medium S fed by the second feeding unit6B.

A main conveying motor 26 drives a main conveying roller 70 which isdisposed upstream of the platen 9 and mainly conveys the printing mediumS being printed. The main conveying motor 26 also drives two conveyingrollers 7 that are disposed downstream of the platen 9 and conveys theprinting medium S conveyed by the main conveying roller 70, furtherdownstream.

A third the conveying motor 27 drives two conveying rollers 7 thatconvey downward the printing medium S the first side of which has beenprinted. The third the conveying motor 27 also drives two conveyingrollers 7 disposed along the inner guide 19. These two conveying rollers7 convey, toward the print head 8, a printing medium S fed from thesecond cassette 5B and conveyed by the second intermediumte roller 71Bor a printing medium S the first side of which has been printed and thefront and back sides have been reversed.

A fourth conveying motor 28 drives two conveying rollers 7 that conveyupward or downward a printing medium S that has been printed. Adischarging motor 29 drives a discharging roller 12 for discharging aprinting medium S that has been printed, to the discharging tray 13. Asdescribed above, the two feeding motors 22 and 23, the five conveyingmotors 24 to 28, and the discharging motor 29 each are associated withone or more drive rollers.

In addition, at eight positions along the conveying path are disposeddetection members 20 for detecting the printing medium S. Each detectionmember 20 includes a sensor and mirror disposed on opposite sides of theconveying path. The sensor having a light emitting unit and a lightreceiving unit is disposed on one side of the conveying path, and themirror is disposed on the other side of the conveying path, at aposition facing the sensor. Each detection member 20 checks whether thelight receiving unit has detected light emitted from the light emittingunit of the sensor and then reflected by the mirror to judge whether aprinting medium S is present, in other words, whether the leading edgeor the trailing edge has passed.

The conveyance control unit 207 drives the feeding motors 22 and 23, theconveying motors 24 to 28, and the discharging motor 29 separately basedon detection results of the multiple detection members 20 and the outputvalues of encoders for detecting the amount of rotation of the driverollers, and thus controls the conveyance operation as the entireapparatus.

The conveyance control unit 207 of the present embodiment, based on theconveyance speed and conveyance mode set for each page, separatelydrives the drive motors connected to the drive rollers supporting eachpage. The above conveyance speed and conveyance mode are set for eachpage by the print controller 202 analyzing a received print job and aremanaged in the RAM 204. Hereinafter, description will be provided for amethod of setting the conveyance speed and conveyance mode.

As for the multiple ejection openings arrayed in the print head 8, thenumber of ejection openings that eject ink at the same time and theejection (drive) frequency of each ejection opening vary depending onimage data. The larger these values, the more likely the powerconsumption exceeds the capacity of the power source of the printingapparatus.

For this reason, in the present embodiment, the drive frequency of theprint head 8 is set for each page depending on the image data, and theconveyance speed of the printing medium S also changes to correspond tothe set drive frequency. For example, when printing a monochromedocument using only black ink, the drive frequency of the print head 8is set relatively high, and the conveyance speed of the printing mediumS is set relatively high. On the other hand, when printing a color imageusing four color inks at high density, the drive frequency of the printhead 8 is set relatively low, and the conveyance speed of the printingmedium S is set relatively low.

FIG. 9 is a flowchart for explaining a conveyance mode setting processexecuted by the print controller 202 when the print engine unit 200receives a print job. Through this conveyance mode setting process, theconveyance speed and conveyance mode are set individually for each ofthe multiple pages included in the same print job. Note that thisprocess is executed by the print controller 202 according to a programstored in the ROM 203, using the RAM 204 as a work area.

When this process starts, the print controller 202 sets a page forprocessing at step S10. When this is the first time to do this step, thefirst page is set as the page for processing.

At step S11, the print controller 202 perform a dot-count process on thepage for processing. Specifically, the print controller 202 inspects theprint data in which dot-printing (1) or no dot-printing (0) is set foreach pixel and counts the number of pixels for which dot-printing (1) isset. In addition, at step S12, the print controller 202 determinesconveyance speed Vb for the page for processing based on the count valueacquired at step S11.

FIGS. 10A to 10C are diagrams illustrating the type of count valueacquired in the dot-count process at step S11 and relationships betweenthe count value of each type and conveyance speed V. FIG. 10Aillustrates the relationship between the count value for the entire pageand conveyance speed V, FIG. 10B illustrates the relationship betweenthe count value for each ink color and conveyance speed V, and FIG. 10Cillustrates the relationship between the count value for a unit area andconveyance speed V.

Count value DC for the entire page means the total count value for allthe ink colors on the entire page. In the present embodiment, asillustrated in FIG. 10A, two thresholds A and B are prepared. When countvalue DC satisfies DC≤A, the conveyance speed is temporarily set as V=26ips (inch/second); when satisfying A<DC≤B, V=14.5 ips; and whensatisfying B<DC, V=8 ips. Here, it is assumed that conveyance speedV=14.5 ips is temporarily set.

Count value DC for each ink color means the count value for each inkcolor on the entire page. In the present embodiment, as illustrated inFIG. 10B, two thresholds C and D are prepared for each ink color. Then,for each ink color, when count value DC satisfies DC≤C, the conveyancespeed is temporarily set as V=26 ips; when satisfying C<DC≤D, V=14.5ips; and when satisfying D<DC, V=8 ips. Here, it is assumed that theconveyance speed for cyan is temporarily set as V=26 ips; for magenta,V=26 ips; for yellow, V=26 ips; and for black, V=14.5 ips, respectively.

Count value DC for each unit area means the total count value for allthe ink colors in a unit area obtained by equally dividing the entirepage in the conveyance direction. The dot count value of a unit areacorresponds to power consumption per unit time. In the presentembodiment, as illustrated in FIG. 10C, two thresholds E and F areprepared. When count value DC satisfies DC≤E, the conveyance speed istemporarily set as V=26 ips; when satisfying E<DC≤F, V=14.5 ips; andwhen satisfying F<DC, V=8 ips. Here, it is assumes that the conveyancespeed is temporarily set as V=8 ips. Note that this conveyance speed Vis set for each unit area.

At step S11, the print controller 202 acquires the multiple countvalues, which are count value DC for the entire page, four count valueDC's for the four ink colors, as many unit-area count value DC's as thenumber of unit areas, as described above. Then, at step S12, the printcontroller 202 temporarily sets conveyance speed V's corresponding tothe respective count values, based on the tables in FIGS. 10A to 10C,and further selects the minimum value among the temporarily setconveyance speed V's as conveyance speed Vb for the page for processing.The determined conveyance speed Vb is stored being associated with thepage for processing.

In this way, by preparing multiple dot count values that are referred towhen the conveyance speed and drive frequency are determined, it ispossible to control print operation such that the power consumption iswithin a range of the specified capacity of the power source even whenthere is an ejection opening array (ink color) or a unit area that makespower consumption high locally. Note that in the present embodiment, itis assumed that tables as illustrated in FIG. 10 are stored in the ROM203 of the print engine unit 200 in advance.

Returning to FIG. 9, at step S13, the print controller 202 determineswhether the page for processing is the second or the subsequent page ornot. In a case where the page for processing is the first page, theprocess jumps to step S16; in a case where it is the second or thesubsequent page, the process proceeds to step S14.

At step S14, the print controller 202 determines whether conveyancespeed Vb for the page for processing is equal to conveyance speed Va forthe preceding page (Vb=Va). In a case where Vb=Va, the print controller202 proceeds to step S15 and sets the conveyance mode of the page forprocessing to “continuous conveyance”. On the other hand, in a casewhere Vb≠Va, the print controller 202 proceeds to step S16 and sets theconveyance mode of the page for processing to “single conveyance”.

At the following step S17, the print controller 202 updates theconveyance speed from conveyance speed Va for the preceding page toconveyance speed Vb for the page for processing and stores the updatedconveyance speed in the memory. Next, at step S18, the print controller202 determines whether the page for processing is the last page of theprint job. In a case where the page for processing is not the last page,the print controller 202 returns to step 510, sets the next page as thepage for processing, and executes the series of the processes describedabove for the new page for processing. On the other hand, in a casewhere it is determined at step S18 that the page for processing is thelast page, this process ends.

Here, description is provided for “single conveyance” and “continuousconveyance”, which are types of conveyance mode. The “single conveyance”is a conveyance mode in which after the discharge process of thepreceding page is completed, the conveyance operation of the page forprocessing starts. Specific description is provided referring to FIG. 8again. When the page for processing is set to the “single conveyance”mode, the conveyance control unit 207 does not drive the first conveyingmotor 24 or the second conveying motor 25 for the page for processinguntil the detection member 20 positioned immediumtely upstream of thedischarging roller 12 detects the trailing edge of the preceding page.Then, after the detection member 20 positioned immediumtely upstream ofthe discharging roller 12 detects the trailing edge of the precedingpage, the conveyance control unit 207 drives the first conveying motor24 or the second conveying motor 25 for the page for processing to startconveying the page for processing. Note that the feeding operation ofthe page for processing may be performed during the print operation ofthe preceding page, or may be started when driving the first conveyingmotor 24 or the second conveying motor 25 is started.

On the other hand, the “continuous conveyance” is a conveyance mode inwhich the conveyance operation of the page for processing starts duringthe conveyance operation of the preceding page.

FIGS. 11A and 11B are diagrams illustrating states during the“continuous conveyance”. Here, in the illustration, the printing mediumto which the page for processing is printed is the succeedingsheetsucceeding sheet S2, and the printing medium to which the page tobe printed immediumtely before the page for processing is printed is thepreceding sheet S1. Here, both sheets are fed from the first cassette5A.

In the case where the page for processing is set to the “continuousconveyance” mode; when the detection member 20 immediumte upstream ofthe main conveying roller 70 detects the trailing edge of the precedingsheet S 1, the conveyance control unit 207 starts feeding the succeedingsheetsucceeding sheet S2, using the first feeding unit 6A. Then, theconveyance control unit 207 stops the first conveying motor 24 with theleading edge of the succeeding sheetsucceeding sheet S2 nipped by thefirst intermediumte roller 71A and leaves the succeeding sheetsucceedingsheet S2 on standby.

At the same time, the conveyance control unit 207 drives the mainconveying motor 26, fourth conveying motor 28, and discharging motor 29according to the conveyance speed set for the preceding sheet Si andcontinues the conveyance operation of the preceding sheet S1. At thistime, the conveyance control unit 207 measures the distance by which thepreceding sheet S1 is conveyed from the time when the above detectionmember 20 detects the trailing edge of the preceding sheet S1, using thecount value of the encoder 21. Then, when the above conveyance distancereaches a specified distance PL. the conveyance control unit 207 drivesthe first conveying motor 24 to start the conveyance operation of thesucceeding sheetsucceeding sheet S2. FIG. 11A illustrates the conveyancestate when the conveyance operation of the succeeding sheet S2 starts.

FIG. 11B illustrates a state where the conveyance has progressed furtherfrom the state in FIG. 11A. The preceding sheet Si is conveyed bydriving the fourth conveying motor 28 and the discharging motor 29, andthe succeeding sheet S2 is conveyed by driving the first conveying motor24 and the main conveying motor 26. For the distance between thetrailing edge of the preceding sheet and the leading edge of thesucceeding sheet, if both conveyance speeds are the same, the abovespecified distance PL is basically kept.

As described above, the “continuous conveyance” means a conveyanceoperation in which while the preceding sheet S1 is being conveyed in theconveying path, the conveyance operation of the succeeding sheet S2 isstarted with the distance to the preceding sheet S1 kept larger than orequal to a certain distance.

FIGS. 12A to 12C are diagrams illustrating conveyance examples performedby the conveyance control unit 207 based on the conveyance speed andconveyance mode set for each page according to the conveyance modesetting process described with reference to FIG. 9.

FIG. 12A illustrates a case where the conveyance speeds are set to thesame values (26 ips) for all the four pages included in a print job. Inthis case, the first page is set to the “single conveyance” mode at stepS16. All the other pages from the second page are set to the “continuousconveyance” mode at step S15.

Specifically, as illustrated in FIGS. 11A and 11B, while the conveyanceoperation of the first page is being performed at a conveyance speed of26 ips, the conveyance operation of the second page is started at thesame speed with an interval of distance PL, and in the same way, theconveyance operations of the third page and the fourth page are startedone after another. With this configuration, the four pages are conveyedat equal intervals and at the same speed, and thus there is littleconcern that a paper jam or the like occurs.

FIG. 12B illustrates a case where, of the four pages included in a printjob, the conveyance speed of the first and second pages is set at 26ips, and the conveyance speed of the third and fourth pages is set at 8ips. In this case, the first and third pages are set to the “singleconveyance” mode at step S16. The second and fourth pages are set to the“continuous conveyance” mode at step S15.

Specifically, while the first page is being conveyed at a conveyancespeed of 26 ips, the conveyance operation of the second page is startedat the same speed with an interval of distance PL. Then, when theconveyance operation of the second page is completed, the conveyanceoperation of the third page is started at a conveyance speed of 8 ips,and during this conveyance operation, the conveyance operation of thefourth page is started with an interval of distance PL at a conveyancespeed of 8 ips. In other words, after the process of conveying two pagesat an identical speed keeping a constant interval is completed, theprocess of conveying another set of two pages at an identical speedkeeping a constant interval. Thus, there is little concern that a paperjam or the like occurs.

FIG. 12C illustrates a case where, of the three pages included in aprint job, the conveyance speed of the first and third pages is set at26 ips, and the conveyance speed of the second page is set at 8 ips. Inthis case, all the pages 1 to 3 are set to the “single conveyance” modeat step S16.

Specifically, after the conveyance operation of the first page at aconveyance speed of 26 ips is completed, the conveyance operation of thesecond page is started at a conveyance speed of 8 ips. After theconveyance operation of the second page is completed, the conveyanceoperation of the third page is started at a conveyance speed of 26 ips.As described above, since the all the three sheets respectivelycorresponding to the three pages are conveyed in the “single conveyance”mode, there is little concern that a paper jam or the like occurs.

As has been described, even when the conveyance speeds of sheetsconveyed in order are different from each other, the present embodimentmakes it possible to perform continuous printing on each sheetefficiently without causing a paper jam or the like.

Second Embodiment

Also in the present embodiment, the inkjet printing apparatusillustrated in FIGS. 1 to 8 is used as in the first embodiment.

FIG. 13 is a flowchart for explaining a conveyance mode setting processexecuted by the print controller 202 of the present embodiment. Thisprocess is different from the first embodiment described with referenceto FIG. 9 in that this process has an additional step S19.

In a case of Vb≠Va, at step S14, the print controller 202 proceeds tostep SI9 and determines whether conveyance speed Vb for the page forprocessing is lower than conveyance speed Va for the preceding page(Vb<Va). In a case of Vb<Va, it is unlikely that the succeeding sheet S2at relatively lower conveyance speed Vb catches up with the precedingsheet S1 at a relatively higher conveyance speed. Thus, the printcontroller 202 proceeds to step S15 and sets the page for processing tothe “continuous conveyance” mode. On the other hand, in a case of Vb>Va,it is highly likely that the succeeding sheet S2 at the relativelyhigher conveyance speed Vb catches up with the preceding sheet S1 at arelatively lower conveyance speed. Thus, the print controller 202proceeds to step S16 and sets the page for processing to the “singleconveyance” mode. The other steps are the same as those in FIG. 9.

FIG. 14 is a diagram illustrating an example of conveyance performed bythe conveyance control unit 207 based on the conveyance speed andconveyance mode set for each page by the conveyance mode setting processillustrated in FIG. 13. Here, of the five pages included in a print job,the conveyance speed of the first, fourth, and fifth pages is set at 26ips, and the conveyance speed of the second and third pages is set at 8ips. In this case, the first and fourth pages are set to the “singleconveyance” mode at step S16. The second, third, and fifth pages are setto the “continuous conveyance” mode at step S15.

Specifically, while the conveyance operation of the first page is beingperformed at a conveyance speed of 26 ips, the conveyance operation ofthe second page starts at a conveyance speed of 8 ips with an intervalof distance PL. After that, while the conveyance operation of the secondpage is being performed at a conveyance speed of 8 ips, the conveyanceoperation of the third page starts next at a conveyance speed of 8 ipswith an interval of distance PL. After that, after the conveyanceoperation of the third page is completed, the conveyance operation ofthe fourth page starts at a conveyance speed of 26 ips. During thisconveyance operation, the conveyance operation of the fifth page startsat a conveyance speed of 26 ips with an interval of distance PL.

As described above, in the case where the conveyance speed of thesucceeding sheet is lower than or equal to that of the preceding sheet,it is unlikely that the succeeding sheet catches up with the precedingsheet. Thus, in the present embodiment, the succeeding sheet is set tothe “continuous conveyance” mode. In the case where the conveyance speedof the succeeding sheet is higher than that of the preceding sheet, itis highly likely that the succeeding sheet catches up with the precedingsheet. Thus, the succeeding sheet is set to the “single conveyance”mode. With this configuration, this embodiment makes it possible toperform continuous printing more efficiently than in the firstembodiment while providing the same advantageous effect as in the firstembodiment.

Third Embodiment

Also in the present embodiment, the inkjet printing apparatusillustrated in FIGS. 1 to 8 is used as in the first embodiment. Here, inthe present embodiment, the conveyance mode of all the pages isbasically set to the “continuous conveyance” mode, but the distancebetween the preceding sheet and the succeeding sheet is adjusted basedon the relative relationship between the two sheets.

FIG. 15 is a flowchart for explaining a conveyance mode setting processexecuted by the print controller 202 of the present embodiment. Theprocesses at steps S10 to S13 are the same as those in the firstembodiment, and here description thereof is omitted.

When the print controller 202 judges at step S13 that the page forprocessing is the second or the subsequent page, the print controller202 proceeds to step S20 and sets inter-page distance PL based onconveyance speed Vb for the page for processing and conveyance speed Vafor the preceding sheet.

FIG. 16 is a diagram illustrating an inter-page distance PL settingtable which the print controller 202 refers to at step S20. In thepresent embodiment, such a table is stored in advance in the ROM 203 ofthe print engine unit 200.

For example, in a case where conveyance speed Vb for the succeedingsheet and conveyance speed Va for the preceding sheet both are at 26ips, inter-page distance PL is set to PL1. In a case where conveyancespeed Vb for the succeeding sheet and conveyance speed Va for thepreceding sheet both are at 14.5 ips, inter-page distance PL is set toPL2. In a case where conveyance speed Vb for the succeeding sheet andconveyance speed Va for the preceding sheet both are at 8 ips,inter-page distance PL is set to PL3. PL1, PL2, and PL3 are adjustablevalues according to the size and type of a sheet (printing medium) andbasically have the relationship of PL1>PL2>PL3. Specifically, forexample, in the case where the sheet is of A4 size, PL1 is approximately87 mm, PL2 approximately 62 mm, and PL3 approximately 48 mm.

As has been described with reference to FIGS. 11A and 11B, when twosheets are conveyed simultaneously in the conveyance path, distance PLbetween the sheets may vary depending on the variation in the drivingforce of various conveying motors and the diameters of the conveyingrollers. The variation is larger when the conveyance speed is higher.Thus, it is desirable that distance PL between the sheets be a distancelarge enough for the succeeding sheet not to catch up with the precedingsheet even when such variation occurs. On the other hand, if theinter-sheet distance PL is set too large, even the continuous conveyancewill not improve the throughput. Thus, in the present embodiment,inter-sheet distance PL in the case where the conveyance speeds of thepreceding sheet and the succeeding sheet are equal (Va=Vb) is set foreach conveyance speed. When the conveyance speed is low, inter-sheetdistance PL is set as low as possible to improve the throughput.

On the other hand, in the case where the conveyance speeds of thepreceding sheet and the succeeding sheet are different, the printcontroller 202 sets inter-page distance PL based on the formulae shownin FIG. 16. For example, in a case where conveyance speed Vb for thesucceeding sheet is lower than conveyance speed Va for the precedingsheet, it is unlikely that the succeeding sheet catches up with thepreceding sheet. Thus, inter-page distance PL is set to a value lowerthan when the conveyance speeds of the preceding sheet and thesucceeding sheet are equal to each other. On the other hand, whenconveyance speed Vb for the succeeding sheet is higher than conveyancespeed Va for the preceding sheet, it is highly likely that thesucceeding sheet catches up with the preceding sheet. Thus, inter-pagedistance PL is set to a value larger than when the conveyance speeds ofthe preceding sheet and the succeeding sheet are equal to each other. Inthis way, an appropriate inter-page distance PL is set at step S20according to the combination of the conveyance speeds of the precedingsheet and the succeeding sheet.

After inter-page distance PL is set at step S20, the print controller202 proceeds to step S21 and determines whether inter-page distance PLset at step S20 is smaller than minimum inter-page distance PLmin set inadvance. Here, minimum inter-page distance PLmin is the minimum distancewith which the conveyance of the preceding page and the following pagecan be individually controlled, which is determined by the arrangementof the conveying rollers 7 and the detection members 20. Specifically,minimum inter-page distance PLmin needs to be larger than the distanceof the farthest combination of all the combinations of adjacent twodetection members 20. In addition, minimum inter-page distance PLminalso needs to be a distance that does not cause a situation in whichmultiple conveying rollers driven by a common conveying motor conveyboth the preceding sheet and the succeeding sheet.

In the case where it is determined at step S21 that PL<PLmin, inter-pagedistance PL currently set does not allow for a normal conveyanceoperation. Thus, the print controller 202 proceeds to step S22, changesinter-page distance PL to minimum inter-page distance PLmin, andproceeds to step S17. On the other hand, in the case where it isdetermined at step S21 that PL>PLmin, the print controller 202 keeps thecurrent inter-page distance PL and proceeds to step S17. The processesafter this process are the same as those in the first embodiment, andthus description thereof is omitted.

FIG. 17 is a diagram illustrating an example of conveyance performed bythe conveyance control unit 207 based on the conveyance speed andconveyance mode set for each page by the conveyance mode setting processillustrated in FIG. 15. Here, of the three pages included in a printjob, the conveyance speed of the first and third pages is set at 26 ips,and the conveyance speed of the second page is set at 8 ips. In thepresent embodiment, the “continuous conveyance” is performed for all thepages, but the length of inter-page distance PL is adjusted according tothe conveyance speeds of the preceding page and the following page. Inthe figure, since the conveyance speed of the second page is lower thanthat of the first page, inter-page distance PL between the first pageand the second page is adjusted to be a value smaller than PL1accordingly. Since the conveyance speed of the third page is higher thanthat of the second page, inter-page distance PL between the second pageand the third page is adjusted to be a value larger than PL3accordingly.

As described above, in the present embodiment, although the “continuousconveyance” is performed for all the pages, inter-page distance PLbetween the preceding sheet and the succeeding sheet is appropriatelyadjusted according to the combination of the conveyance speeds of thepreceding sheet and the succeeding sheet. With this configuration, thisembodiment makes it possible to perform continuous printing moreefficiently.

Note that although in the above, the drive frequency of the print headand the conveyance speed of the printing medium are adjusted on purposethat power consumption will not exceed the specified capacity of thepower source provided for the printing apparatus, the present inventionis not limited to this case. For example, it is known that an inkjetprint head has a limit to the drive frequency (refill frequency) forperforming normal ejection operation at each ejection opening. Thus, thedrive frequency of the print head and the conveyance speed of theprinting medium may be adjusted not to exceed this limit. In addition,in the case where the temperature of the print head or the type ofprinting medium changes on an individual page basis, the drive frequencyof the print head and the conveyance speed of the printing medium may beadjusted according to the temperature and the type. In any case, thepresent invention fully provides the advantageous effect in thesituation where the conveyance speed is set on an individual page basiswhen printing multiple pages continuously.

In the above, the description has been provided for the configuration inwhich the print controller 202 of the print engine unit 200 sets theconveyance speed and conveyance mode for each page and the inter-pagedistance, and the conveyance control unit 207 performs conveyancecontrol based on the set values. However, the present invention is notlimited to this configuration. For example, the conveyance mode settingprocess described using the above flowcharts may be performed by themain controller 101 or image processing unit 108 of the controller unit100. In this case, the conveyance speed and conveyance mode for each ofthe multiple pages included in a job and other information aretransferred to the print engine unit together with the print data ofeach of the multiple pages.

In addition, in the above, the description has been provided for theconfiguration in which after the print controller 202 sets theconveyance speed and conveyance mode for all the pages, the conveyancecontrol unit 207 performs conveyance control continuously for all thepages based on the set values. However, the present invention is alsonot limited to this configuration. Using, as a trigger, the time whenthe print controller 202 sets the conveyance speed and conveyance modefor a page, the conveyance control unit 207 may start the feedingoperation and conveyance control for the page.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2017-243016 filed Dec. 19, 2017, which is hereby incorporated byreference wherein in its entirety.

1.-14. (canceled)
 15. A printing apparatus comprising: a conveyance unit configured to convey a first printing medium and a second printing medium that follows the first printing medium along a conveying path; a print unit disposed in the conveying path and configured to print on a printing medium according to print data; and a control unit configured to control the conveyance unit, wherein in a case in which a second conveyance speed of the second printing medium is higher than a first conveyance speed of the first printing medium, the control unit starts a conveyance operation of the second printing medium after the first printing medium is discharged from the conveying path.
 16. A printing apparatus according to claim 15, wherein in a case in which the second conveyance speed is equal to the first conveyance speed, the control unit starts conveyance of the second printing medium before the first printing medium is discharged from the conveying path.
 17. The printing apparatus according to claim 16, wherein in a case in which the second conveyance speed is lower than the first conveyance speed, the control unit starts conveyance of the second printing medium while the first printing medium is being conveyed in the conveying path.
 18. The printing apparatus according to claim 16, wherein the control unit is further configured to set the first conveyance speed according to first print data and set the second conveyance speed according to second print data.
 19. The printing apparatus according to claim 18, wherein the control unit sets the first conveyance speed based on a result of counting a number of dots to be printed by the print unit according to the first print data, and sets the second conveyance speed based on a result of counting a number of dots to be printed by the print unit according to the second print data, and the larger a count value indicating each of the results of counting, the lower the speed at which the control unit sets the corresponding one of the first conveyance speed and the second conveyance speed.
 20. The printing apparatus according to claim 15, wherein in a case in which the second conveyance speed is lower than the first conveyance speed, the control unit starts conveyance of the second printing medium while the first printing medium is being conveyed in the conveying path.
 21. The printing apparatus according to claim 15, wherein the control unit is further configured to set the first conveyance speed according to first print data and set the second conveyance speed according to second print data.
 22. The printing apparatus according to claim 21, wherein the first print data and the second print data are included in the same print job.
 23. The printing apparatus according to claim 15, further comprising: a feeding unit configured to feed a printing medium from a cassette in which a plurality of printing media are stored and guide a leading edge of the printing medium to the conveying path, wherein while the conveyance unit is conveying the first printing medium in the conveying path, the control unit causes the feeding unit to feed a leading edge of the second printing medium to the conveying path.
 24. The printing apparatus according to claim 15, wherein the print unit is provided with a line type print head.
 25. The printing apparatus according to claim 15, further comprising a tray configured to stack printing media discharged from the conveying path, wherein in the case in which the second conveyance speed is higher than the first conveyance speed, the control unit controls the conveyance unit such that a conveyance operation of the second printing medium starts after the first printing medium is discharged to the tray from the conveying path. 